James Gandolfini, star of HBO’s “The Sopranos,” has died of a possible heart attack in Rome. He was 51.

A spokeswoman for the cable network said that Gandolfini was on holiday in Italy. They were preparing a more complete statement.

Gandolfini, a burly man with a booming voice, had recently filmed “Criminal Justice” for HBO, which had received a limited series order.

As Tony Soprano, he anchored a show that ushered in what many consider a new golden era of television. The series invited viewers to sympathize with the bad guy, and only Gandolfini’s charm made it possible to root for Tony even as he cheated on his wife and betrayed his loved ones.

Gandolfini walked a tough line, asking us to understand Tony without necessarily liking him. But in spite of ourselves, we usually did.

“The Sopranos” is widely cited as one of the best in the history of television. It opened the door for similarly daring series including HBO’s “The Wire,” AMC’s “Mad Men” — created by “Sopranos” alum Matthew Weiner — and AMC’s “Breaking Bad,” which also features a criminal protagonist.

One of Gandolfini’s breakthrough roles was playing a similarly sympathetic wiseguy in “True Romance,” written by Quentin Tarantino. He also showed his gentle side in “Where the Wild Things Are,” playing wild thing Carol as a depressed middle-aged malcontent.